The present disclosure relates to a senor, and more particularly, to a sensor capable of improving shock-proof and sensitivity.
As an interest in recent living environmental pollution and health increases, necessity for sensing various environmental toxic gases is greatly increased. Toxic gas sensors having been developed by demands on sensing toxic gases and exploded gases are in a high demand due to needs for health care, living environment monitoring, industrial safety, home appliances and smart home, and improvement of the quality of human life for national defense and terrorism. Accordingly, a gas sensor becomes a means for realizing a society without a disaster and to this end, more precise measurement and controls for the environmental toxic gas are required than before.
Gas sensors may be classified into a semiconductor type gas sensor, a solid electrolyte gas sensor, and a catalytic combustion gas sensor according to a form, structure and material. The semiconductor type gas sensor among them has a large output change at a low concentration to have high sensitivity and be durable. Since operating at about 100° C. to 500° C., the semiconductor type gas sensor includes a sensing electrode for sensing a resistance change, a sensing material coated on the sensing electrode, and a heater (heating element) for raising a temperature of the sensing material. When the semiconductor type gas sensor is heated by a heater and a gas is adsorbed to the sensing material, the semiconductor type gas sensor measures an electrical characteristic change occurring between the sensing electrode and the sensing material by the adsorbed gas.
However, the semiconductor gas sensor does not normally operate, when adhesion between a sensing material and a sensing electrode is unstable or poor. In other words, since the semiconductor gas sensor has a structure that a sensing electrode is formed on a flat substrate and a sensing material is coated thereon, adhesion between the sensing electrode and the sensing material is very weak to an external shock. In addition, when, for example, a metal oxide semiconductor is used as a sensing material, an operation temperature of the semiconductor gas sensor is relative high as 250° C.˜400° C., a phenomenon that the sensing material is desorbed due to a heat shock according to repetitive operations.
In addition, in typical gas sensors, a sensing electrode and an external electrode for PCB mount is connected by using wire bonding. An example of such a gas sensor is disclosed in Korean Patent Application Laid open Publication No. 2004-016605. However, the wire bonding is weak to an external shock and has difficulty in mass production.